As shown in FIG.1,the U.S. pat. application Ser. No.08/672,859 filed by this inventor as the same as the present invention discloses a socket 20 having a driven end 22 which is provided in the inner wall thereof with two grooves 221 diagonally opposing each other. The driven end 22 is further provided in proximity of one end thereof with a circular slot 222.An elastic body 24 is fitted into the fitting end 22 of the socket 20 such that a retaining side 241 of the elastic body 24 is retained in the grooves 221 of the fitting end 22,and that a curved end portion 244 of the elastic body 24 urges against the circular slot 222 of the driven end 22. As a result, a protruded edge 242 of the retaining side 241 of the elastic body 24 is capable of retaining a nut which is engaged with the driven end 22 of the socket 20.In the meantime, the retaining side 241 is capable of preventing the elastic body 24 from slipping out of the socket 20 at the time when the nut is taken out of the socket 20. The elastic body 24 is further provided with a bottom portion 243 having an arcuate configuration.
As shown in FIG.2, the U.S. pat. application Ser. No.08/998,686 filed by this inventor of the present invention discloses a socket spanner with a nut retaining device which is intended to overcome the structural deficiency of the socket spanner disclosed in the afore-mentioned U.S. pat. application Ser. No.08/672,859 and is composed of a circular slot 222 located in the bottom of the driven end of the socket. The elastic body is thus fitted into the driven end such that the arcuate bottom portion 243 of the elastic body is retained in the circular slot 222 so as to facilitate the removing of the nut which is engaged with the fitting end of the socket.
The socket spanners disclosed in the U.S. pat. application Ser. Nos.08/672,859 and 08/998,686 share a common structural deficiency in that they are provided with a circular slot 222 which can not be easily lathed with precision.